Don't install Ruby or Python dependencies unnecessarily (#7084)

* Don't install Ruby or Python dependencies unnecessarily

* Less repeated code

* Cleaner code

packages/build-utils/src/convert-runtime-to-plugin.ts

@@ -52,6 +52,9 @@ export function convertRuntimeToPlugin(
           includeFiles: config.includeFiles,
           excludeFiles: config.excludeFiles,
         },
+        meta: {
+          avoidTopLevelInstall: true,
+        },
       });
 
       pages[entrypoint] = {

packages/build-utils/src/types.ts

@@ -58,6 +58,7 @@ export interface Meta {
   filesRemoved?: string[];
   env?: Env;
   buildEnv?: Env;
+  avoidTopLevelInstall?: boolean;
 }
 
 export interface AnalyzeOptions {

packages/python/src/install.ts

@@ -1,3 +1,4 @@
+import { relative, basename } from 'path';
 import execa from 'execa';
 import { Meta, debug } from '@vercel/build-utils';
 
@@ -135,6 +136,18 @@ export async function installRequirementsFile({
   meta,
   args = [],
 }: InstallRequirementsFileArg) {
+  const fileAtRoot = relative(workPath, filePath) === basename(filePath);
+
+  // If the `requirements.txt` file is located in the Root Directory of the project and
+  // the new File System API is used (`avoidTopLevelInstall`), the Install Command
+  // will have already installed its dependencies, so we don't need to do it again.
+  if (meta.avoidTopLevelInstall && fileAtRoot) {
+    debug(
+      `Skipping requirements file installation, already installed by Install Command`
+    );
+    return;
+  }
+
   if (
     meta.isDev &&
     (await areRequirementsInstalled(pythonPath, filePath, workPath))

packages/ruby/index.ts

@@ -1,4 +1,4 @@
-import { join, dirname } from 'path';
+import { join, dirname, relative } from 'path';
 import execa from 'execa';
 import {
   ensureDir,
@@ -85,10 +85,12 @@ export async function build({
 }: BuildOptions) {
   await download(files, workPath, meta);
   const entrypointFsDirname = join(workPath, dirname(entrypoint));
+  const gemfileName = 'Gemfile';
+
   const gemfilePath = await walkParentDirs({
     base: workPath,
     start: entrypointFsDirname,
-    filename: 'Gemfile',
+    filename: gemfileName,
   });
   const gemfileContents = gemfilePath
     ? await readFile(gemfilePath, 'utf8')
@@ -130,6 +132,14 @@ export async function build({
         'did not find a vendor directory but found a Gemfile, bundling gems...'
       );
 
+      const fileAtRoot = relative(workPath, gemfilePath) === gemfileName;
+
+      // If the `Gemfile` is located in the Root Directory of the project and
+      // the new File System API is used (`avoidTopLevelInstall`), the Install Command
+      // will have already installed its dependencies, so we don't need to do it again.
+      if (meta.avoidTopLevelInstall && fileAtRoot) {
+        debug('Skipping `bundle install` — already handled by Install Command');
+      } else {
         // try installing. this won't work if native extesions are required.
         // if that's the case, gems should be vendored locally before deploying.
         try {
@@ -141,6 +151,7 @@ export async function build({
           throw err;
         }
       }
+    }
   } else {
     debug('found vendor directory, skipping "bundle install"...');
   }

packages/ruby/install-ruby.ts

@@ -61,6 +61,14 @@ function getRubyPath(meta: Meta, gemfileContents: string) {
 // process.env.GEM_HOME), and returns
 // the absolute path to it
 export async function installBundler(meta: Meta, gemfileContents: string) {
+  // If the new File System API is used (`avoidTopLevelInstall`), the Install Command
+  // will have already installed the dependencies, so we don't need to do it again.
+  if (meta.avoidTopLevelInstall) {
+    debug(
+      `Skipping bundler installation, already installed by Install Command`
+    );
+  }
+
   const { gemHome, rubyPath, gemPath, vendorPath, runtime } = getRubyPath(
     meta,
     gemfileContents